Allaround4x4

A day ago I posted about finding oil in my #2 spark plug socket. Now that I got that issue cleared up, I've got more pronounced symptoms.

Since the first day I purchased this pickup, I've had an issue with the shifting and acceleration. It struggles to shift gears. I have to let off the throttle entirely to get it to shift up and then have to bury the throttle, let off to get it to shift down. It shifts into overdrive way early, like 1000rpm cruising at 30mph, which doesn't seem right to me. As far as acceleration goes, it was really bad when I got the pickup. When pressing in on the throttle, it would bog down and sometimes kill itself. I replaced the TPS and it fixed the throttle problem, until yesterday.

Yesterday everything got worse after fueling up. It would bog down and stutter upon pushing in the throttle and wouldn't stop until I had pumped the pedal several times. I changed the fuel filter to see if this was the issue but it still did it. I checked the spark plugs which is when I found the oil on #2, which turned out was just spillage.

So today I decided to try something I've never thought or heard of before which was resetting the PCM. As far as I know, I've done it correctly. The acceleration issue is still there but not nearly as bad. I test drove it to reset values which is when I noticed some new things I've never noticed before.

#1. There is a pretty rough misfire somewhere. The engine idles very rough and I can hear the misfire.

#2. When arriving upon a shift point, the transmission seems like it's trying to shift but it can't decide whether to or not. It isn't slipping so to speak like a clutch is bad, it's like itsome sticking in between gears like it can't decide. The RPM stays where it's at and will not move without some heavy throttle. This also causes a small but rapid succession of backfires.

#3. When in park, it idles rough (stated above). If I throttle up to around 2000 - 3500 RPM, it does the rapid backfire again. Small, but rapid.

I'm used to full mechanical engines like what's in the 70s pickups so I'm not too good a diagnosis of these computer controlled engines. I've done a few upgrades to this pickup such as injectors, MAF, and air intakes. I replaced the proper sensors when doing this however so I'm kind of at a loss. It's bugging the heck out of me. It was mentioned to me by a diesel mechanic friend that my PCM or ECU might be going bad. I don't know where to start diagnosing or what to even look at first.

Has anyone ever a had these symptoms before or similiar? Possible one at a time?

w0lvez

Your Injector is too big for your pump. Your loosing fuel pressure when the injector opens because of the flow rate of your fuel pump. You need to have a stable pressure of 39.15psi in the fuel rail.

Allaround4x4

It's not the fuel pressure. I've got 51.23 psi at the fuel rail with 95 lb injectors. Like I said in my previous posts, I have 2 fuel pumps to increase flow to the injectors

w0lvez

Your fuel pressure is too much. The PCM is caliberated to work at 39.15psi. You need to change your fuel supply line to reduce the pressure.

w0lvez

Your Catalytic Converter could be clogged causing it to backfire.

screamineagle

If you added an oiled air filter, that's considered a downgrade. If so, replace with a factory paper filter and clean the MAF. Good luck!

ScrewThat

First off..what all is done to the truck to constitute a second fuel pump and upgraded injectors.

Secondly..I'm guessing by backfire you mean pops in the exhaust? Do you have any way to check the fuel trims? You're sure you're not running rich?

Allaround4x4

The truck is a work in progress. I received it on a trade and decided to turn it into a toy. The injectors were the first thing I wanted to do because I'm adding a supercharger in the near future. Being as I added 95 lb injectors, I decided to add a secondary pump to increase flow to the injectors. I've ran it with this setup for almost 8 months now with it never doing this.

And yes exactly what I mean by backfire is a rapid succession of pops. I assumed these were small backfires.

I don't have an inkling of an idea as to how to check or change fuel trims. And yes it does kind of smell a little rich now that I think about it.

Bit would this have to so with shift point problems and issues shifting the automatic transmission?

screamineagle

Holy crap! Return your fuel system to stock and I bet your problems will disappear. It's also a very good possibility that your cats may be trashed due to running rich.

Allaround4x4

I am in the process of installing the stock injectors right now to see if this is the throttle problem. I'm still confused as to the shifting issue. My fluid looks great and it's not low or overfilled